Anyone who has been paying attention to the news in London lately will know that construction on Crossrail One has begun 20 metres below the ground parallel to Oxford Street near Soho Square. The big news in the music press has been the closure of the Astoria Theatre, but the construction holds far more significance for the vibrant post production community that exists in the area. While this new route will be ideal for commuters, there are questions over how vibrations and noise from the new line will affect this work and with plans for Crossrail Three already underway, it seems the new lines could affect many studios in the area.

To understand the process of this project, one has to accept that it was, and is, Crossrail’s job to deliver a design to the contractors for the new underground railway that would have the lowest possible construction costs, while meeting the objectives of the Bill passed by Parliament. A great deal of environmental PR was attached to the stated objectives for Crossrail, but anyone working in sound in Soho will know that the required understanding of ‘quiet’ is not one recognised by people and regulatory bodies outside our industry.

Two years prior to the beginning of construction of Crossrail One, the owners of Grand Central Post Production on Great Marlborough Street began serious research into the effects that a train line running 20 metres below its building might have on voice recording, sound design, editing and mixing projects at the studio. Grand Central enlisted the services of some heavy hitting experts in the shape of White Mark, Capita Symonds and Dr Hugh Hunt of Cambridge University’s Department of Engineering to help present their concerns at the Parliamentary Enquiry into Crossrail.

While the issue for many studios was potential noise and vibration disturbance, Transport For London’s (TFL) main concern was designing and getting the railway built as economically as possible. The original TFL proposal that 35dB LA max is a noise level that, only if exceeded, would be disrupting to the work performed at a studio, was deemed completely unacceptable. Significantly, to get the noise level below 35dB LA max would require advanced and extensive noise and vibration mitigation to be applied to the area of the track running under Grand Central. After many meetings with TFL, Grand Central’s solicitors and their Queen’s Council, an acceptable maximum noise level within the studio areas was finally determined. This new benchmark is based on a third octave analysis of the background noise and sets a level that is below the NC25 mark specified for dubbing theatres by both Dolby and the relevant BS standard. This level is now known as the Grand Central Criteria.

White Mark’s MD, David Bell, was heavily involved in the processes of establishing the new limit. He explains: “The Crossrail Commission was saying that the noise in the building would be no more than 35dB LA max. I have heard this and it is quite loud in the context of studio monitoring conditions. It was predicted to be predominantly quite low in principal frequency content. You might have been able to filter it out but this would compromise the integrity of voice recordings severely.”

In addition to the Grand Central Criteria, other considerations were achieved by Grand Central’s team regarding the engineering and design of the track during construction as well as the finished line. The Commission agreed to move the joints of the new track to a minimum distance of 100 metres on either side of Grand Central Studios and float the track that will run under the studio. Bell comments: “The new floating track will consist of rails that are decoupled from the track’s sleepers, and the sleepers themselves will sit on a concrete bed which is itself decoupled from the tunnel structure. With all these measures in place, Grand Central should be well protected from any noise from the new track once it is in operation.

“Grand Central spent an enormous amount of time and money to make sure it would be protected from any disturbances of the new rail line. In the beginning of the process it was claimed that the noise from the track would not be any louder than the existing tube lines underneath Soho. This may have relevance for a building which is the same distance from Crossrail as it is from a current operating tube line, but is of no comfort to a studio that has been carefully sited at a safe distance from, say, the Central Line and was faced with a new railway directly beneath it. 

“The bottom line is that there are people in the community that have put their life’s work on the line and everything they own to build a business based in their studio complex and the question for them was: in three months time are my clients going to stop coming? This was a stark question to ask within the framework of the adversarial system of the enquiry. It is perhaps not the best environment to try and arrive at an intellectual consensus, but this is what has been achieved. In the beginning, I thought that it would just take a meeting or two with their experts in order to reach an agreement, but it took a year and a half of work for a lot of people, a great deal of money and many meetings with solicitors present and explanations through QCs to eventually achieve an acceptable concensus.”

As part of this agreement, a monitoring regime for measuring the compliance by the constructors and operators of the railway to specified construction noise levels together with the Grand Central Criteria for the completed railway has been established. If these criteria are breached then the agreement allows for the reconstruction of the lower ground floor studios at the expense of the Secretary of State.

Construction work has now begun and it is only a matter of time before the line will be finished and trains running. Grand Central and White Mark are confident that the measures put in place will provide adequate protection from noise generated by the track, but the effects on studios outside the area where the track is floated are less certain. “Studios that do not have low frequency isolation may be effected,” Bell continues. “Another concern is Crossrail Three, which is set to run somewhere between Piccadilly Circus and Tottenham Court Road. If studios have taken reasonable steps to isolate themselves from low frequency noise, then they should be okay. If studios in the Soho area have concerns after having listened to what TFL is saying, then they should talk to a person such as me or another acoustician for an explanation as to what the development will mean for them. The Crossrail project has pledged to spend a significant extra sum to achieve the floating tracks and offer protection to the studios in the vicinity, but when you think that the cost of relocation of even one studio complex, should this have become necessary, could well be a comparable amount, this is a more than reasonable sum for the railway, for the tax payer and for the post community in Soho.”

Although Grand Central’s actions were undertaken to protect the studio from the effects of Crossrail, there was also concern on behalf of Soho’s post production environment as a whole to debunk rumours that the new line caused excessive low frequency noise. TFL has worked with Grand Central to ensure this risk is now virtually eliminated. The benefits of the increased accessibility that the rail system will in time provide will only help the area enhance its pre-eminent position in the world of film and television production.
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